Magnetic separator.



wm 1 cases Patented Apr. 80, 1912.

2 SHEETS-SHEET 1.

J. WEATHERBY, JR.

MAGNETIC SEPARATOR.

APPLICATION FILED SEPT. 16, 1910.

Patented Apr. 30, 1912.

2 SHEETSSHEET 2.

UNITED STATES PATENT OFFICE.

JOSEPH WEATHERBY, JR., OF NEW CUMBERLAND, PENNSYLVANIA, ASSIGNOR '10 ANDREW J. DULIL, 0F HARRISBURG, PENNSYLVANIA.

MAGNETIC SEPARATOR.

Specification of Letters Patent.

Patented Apr. 30, 1912.

To all whom it may concern:

Be it known that I, JOSEPH WEATHERBY, J r., a citizen of the United States, residing at New Cumberland, in the county of Cumberland and State of Pennsylvania, have invented certain new and useful Improvements in Magnetic Separators; and I do hereby declare the following to be a full, clear, and exact description of the same, reference being had to the accompanying drawings, and to the letters and figures of reference, forming a part of this specification.

This invention relates to magnetic separators and more especially to that type of magnetic separator designed for operating upon comminuted ores for the separation or classification of the materials forming the ores in accordance with the magnetic susceptibility or permeability of such materials.

One of the objects of the invention is to provide a separator through which the materials may be passed in a constant uniform stream.

A further object of the invention is to provide a compact machine having no parts liable to become disarranged or broken and capable of operating upon and separating not only materials having high and widely different magnetic susceptibility, but also materials having but slight magnetic susceptibility or permeability, or diflering but slightly in magnetic susceptibility, thus adapting the machine for use in the separation either of magnetite, or of practically any of the low grades of ore which do not exist naturally in what would ordinarily be considered a magnetic condition.

The invention contemplates the separation of the materials by passing the same transversely through a plurality of annular divergent gaps in a magnetic circuit or circuits wherein the lines of magnetic influence are very dense' and converge toward the outer side of the field and in providing mechanical means whereby the more susceptible material is mechanically advanced and removed from the magnetic influence while the tailings travel by gravity alone transversely through the successive dense fields of magnetic influence, thereby insuring the removal of all susceptible material.

. In the practical embodiment of the apparatus for carrying the present invention into practice and adopted for illustrative purposes herein, the magnetic field is produced within annular pole pieces having' frusto-conical faces; a conical screen set at the proper angle and rotated at sui'licient speed to cause the more susceptible materials to be advanced toward the discharge by centrifugal force is provided and an internal substantially conical guide, formed in part by an armature whereby the lines of force are condensed and caused to converge toward the poles of the external field magnets, constitutes the means whereby the materials of less susceptibility are guided to travel by gravity alone down through and transversely of the annular magnetic fields.

Referring to the accompanying drawingsFigure 1 is an elevation of a magnetic separator embodying the present improvements and Fig. 2-is a sectional elevation on an enlarged scale with parts broken away.

While any desired form of sup orting and adjusting mechanism might be employed, a novel and compact arrangement is shown in the accompanying drawings; that is to say, in a suitable base A there is mounted a series of vertical posts or standards A which, at their upper ends, are adjustably connected with lugs b projecting from .or connected-with the outer face of a ring B of magnetic material. The ring B constitutes the body of the field magnet offth e apparatus, the magnetizing coils C being located within a chamber 0 opening into the body of the ring from the inner or conical face.

While the pole pieces may be of different formations, it is preferable that the upper pole piece B be made integral with the ring R while the lower pole piece 13 is separate and in the form of a ring adapted to seat in the under side of the ring B after the coils C are properly positioned. The pole piece B is rigidly held in intimate contact with the body of the field magnet by screws 6 as shown in Fig. 2. The inner faces of the pole pieces are of frusto-conicalform and are preferably substantially in alinement with each other, the interval between the proximate corners or edges of the pole pieces being bridged so as to protect the coils by a non-magnetic sheet or ring D. As thus constructed, the body of the field magnet, uprights and bases constitute a rigid structure upon which the other parts of the apparatus may be conveniently mounted for proper adjustment and operation.

The hopper E, is mounted on the upper ends of the uprights E secured in the upper face of the ring B and has a downwardly projecting centrally disposed discharge spout E in which is located a feed ad usting gate F, said gate being supported by handles 7 projecting through slots f in the feed spout and screwing into the gate. Immediately below the feed spout and in position to receive the materials discharged therefrom is the upper and preferably outwardly flaring end of a rotary screen support G. This screen support G is of proper size to fit with a fair degree of accuracy within the central aperture at the top of the field magnet B and it is supported on said magnet or ring R by annular hall-l')earings g ahd is adapted to be rotated through the medium of a belt applied to the crown pullcy H rigidly secured to its upper edge. Depending from the screen support G and traveling in proximity to the frusto-conical faces of the pole pieces is a conical imperforate screen 1. The lower ends of the screen are strengthened and guided by a strengthening ring 2' having a conical hearing face engaging the fixed bearing '1" on the lower edge of the ring B. To prevent the entry of dust a cover plate i'- is bridged across the joint between the fixed and movable bearings 2' 2'.

The screen I is of non-magnetic material, imperforate. and adapted to operate centrifugally in feeding the more susceptible material through and away from the magnetic fields in proximity to the pole pieces.

Arranged centrally of the screen and ring B is a substantially conical guide over the conical face of which the material from the hopper is caused to travel by gravity in proximity to the pole pieces in succession and. inasmuch as the form of this guide is of some importance. it will be described with particularity, the fact being borne in mind. however, that the essential feature resides in a conical guide having means whereby the material traveling down over its surface may be retarded in its movement and pltftltlblY means whereby such material will be dropped away from the surface of the guide where it can be freely acted upon by the magnetic energy and readily disentangle itself from the less susceptible material. The body of the conical guide, which constitutes a fixed armature for the annular field magnet is indicated by the letter K. It is centrally provided with a conical cap is rigidly connected therewith but preferably always of non-magnetic material, and its surface is provided with shoulders or steps K, one preferably arranged to retard the flow of material just before or as it enters the upper magnetic field and the other arranged -to retard the flow of material immediately before or as it enters the field of force diverging from the lower pole piece. From the lower step or shoulder the guidepreterablycurvessharply down so as to discharge the materials freely, the materials discharged over the lower edge of the guide being ordinarily the tailings which are of less susceptibility. all materials of greater susceptibility having been drawn to the rotating screen and discharged from the lower edge of said screen by centrifugal force. Between the lower edge of the screen and the outer lower edge of the guide there erected an annular partition M and outside of said partition, and surrounding the ring B is an int-losing ring or casing N. The rings M and X constitute the upper edges of receptacles for the 'tailings and heads respectively, and said rings. together with the armature are preferably directly supported upon a vertically adjustable spider 0, whereby they may be adjusted in unison so as to vary both the width of the passage-way through which the materials travel between the pole pieces and the arn'iature and the position of the edge of the partition on opposite sides of which the tailings and heads fall. Depending below the spider O and forming continuations of the rings M and N are inverted cones or funnel-shaped receivers M and N, respectively, terminating in chutes M and N through which the tailings and heads are discharged.

The spider O is conveniently guided on the uprights A and supported by sleeves O which latter are, in turn, supported on a second spider 0 the latter bearing upon a centrally arranged hand wheel nut adjustahle vertically on a central screw projecting upwardly from the base A.

Clogging or bridging of the material in the hopper E is prevented by a rotary stirrer l. the lower edge of which is adapted to cooperate with the gate F in regulating the rate of feed. This stirrer P is mounted on a stem 2) projecting upwardly from the center or hub 71, of the crowned pulley It so as to rotate with the pulley.

The material discharged from the hopper into the upper end of the screen support might, by reason of the speed at which said support rotates, tend to adhere to the inner walls of the support, and in order to remove any such material a scraper R is hung loosely on a central conical bearing R projecting downwardly from the stem p. The ends of the scraper R are shaped to con' form to the inner wall of the screen support. The scraper is normally held against rotation by upwardly projecting stop pins S supported by the central conical guide K.

The magnetic circuit of the field magnet and armature it will be observed includes a gap at'the inner side forming dense fields of magnetic intensity through which the material to be separated is passed. The pole pieces of the field magnet are of opposite sign, thus effecting a more perfect separation, probably because of the charge im parted to the material in passing through one field, whereby it is rendered more susceptible to the magnetic influence of the succeeding field of opposite sign. The shape of each of the continuous annular poles of the field magnet is such that it converges at the tip. The tips are in proximity to the armature and the latter of greater area and preferably of less conductive capacity for equal areas than the poles, whereby although the field magnet v may be of greater diameter, the lines of magnetic force concentrate outwardly and tend to move the susceptible material outwardly or away from the armature. V

In the separation of certain materials it is important to effect the separation in a manner which will prevent the entanglement of the materials in such manner that the object sought would be defeated. For instance, if the more susceptible material is capable of being inductively magnetized it will when within the zone of magnetic influence, tend to bunch together, and move ment will be retarded at the instant when magnetic force is beginning to act. This result is obtained by the interposition of the shoulders K on to which the material drops and from which it flows only when its angle of rest is exceeded. The action of the construction is such that for an instant the material is free in the air,'at which time the magnetic attraction acts nearly in line with the direction of travel of the materials and has every opportunity to withdraw the more susceptible materials from among the less susceptible materials leaving the latter free in its downward travel under the action of gravity.

It will be noted that the retarding of the movement of the material and the dropping of the material onto the shoulder does not project it against the rotating screen, this being important because of the fact that a. particle of any character once contacting with the screen will be held against the screen until discharged with the heads atthe lower edge of the screen.

By retarding the movement of the material it is presented in the dense magnetic field and thus destroying its momentum it has but a slight tendency, under the influence of gravity, to move away from the annular pole pieces of the field magnet.

Material which would otherwise flow through without separation is thus readily separated from the tailings.

What I claim is: l

1. The improvement in separating comminuted materials of different magnetic susceptibility, which consists in feeding the more susceptible and separated material by centrifugal force and the less susceptible and unseparated material by gravity alone transversely through and away from fields of magnetic intensity arranged in succession in proximity to each other and in mechanically retarding the movement of the less susceptible and unseparated material at a point in proximity to one of said fields of magnetic intensity to prevent slightly susceptible material from being carried through the magnetic field by momentum.

2. The improvement in separating comminuted materials of different magnetic susceptibility, which consists in feeding the -more susceptible and separated material by centrifugal force and the less susceptible and unseparated material by gravity alone transversely, through and away from fields of magnetic intensity arranged in succession in proximity to each other and in mechanically retarding the movement of the less susceptible and unseparated material at points in proximity to each of said fields of magnetic intensity to prevent slightly susceptible material from being carried through the magnetic fields by momentum.

3. The improvement in separating comminuted materials of different magnetic susceptibility, which consists in continuously feeding the more susceptible material by centrifugal force and the less susceptible material by gravity, through and away from annular fields of magnetic intensity arranged in succession in proximity to each other and in temporarily mechanically retarding the movement of the less susceptible material at a point in proximity to one of said fields of magnetic intensity whereby its momentum is checked and interference thereby with magnetic act-ion prevented.

4. A magnetic sepaator embodying a circular magnet having internal annular pole pieces of opposite sign with inner frustoconical faces substantially in alinement with each other, a rotary conical screen located within the pole pieces and a substantially conical armature forming a guide within the screen whereby all the material to be separated is caused to travel between the armature and screen and past and in proximity to the pole pieces in succession.

5. A magnetic separator embodying annular magnetic pole pieces with frusto-conical inner faces substantially in alinement with each other, a rotary conical screen located within the pole pieces and a guide within the screen having a substantially conical outer face with shoulders thereon for retarding the flow of material under the influence of gravity.

6, In a magnetic separator, the combination with the circular field magnet having annular internal pole pieces with conical faces, vertical supports on which said field magnet is mounted and a base for said support, of a conical screen journaled on the field magnet to rotate in proximity to the pole pieces and having a feed opening at the apex, an internal substantially conical guide extending from the feed opening down past both pole pieces and over which the material flows under the influence of gravity, a vertically movable support for said guide, and an adjusting mechanism for said support.

7. In a magnetic separator, the combination with the circular field magnet having annular internal pole pieces with conical faces, vertical supports on which said magnet is mounted, and a rotary screen adapted tomove inproximity to the pole pieces, of an internal substantially conical guide, a vertically movable support for said guide, guided by the field magnet supports below the magnet, and means for adjusting said guide support.

8. In a magnetic separator, the combina: tion with the circular field magnet having internal pole pieces with annular conical faces and tips of reduced area and magnetizing coils located Within the body of said magnet, of a conical screen adapted to rotate in proximity to the faces of the pole pieces within the circular magnet, and a substantially conical armature located within the screen and forming with said screen a conical passageway past all the pole pieces through which the materials to be separated are passed in proximity to the pole pieces, said armature having a greater area than the tips of the pole pieces whereby the lines of magnetic force converge outwardly.

9. In a magnetic separator, the combination with the circular magnet having internal-pole pieces of opposite sign separated from each other and provided with internal annular conical faces, a non-magnetic conical screen journaled ,to rotate in proximity to said pole pieces, a feed duct having an aperture opening into the apex of said conical screen through the center of the field magnet and an armature forming a guide within the screen for directing the material to be separated along divergent lines in proximity to the pole pieces.

10. A magnetic separator embodying a circular magnethaving internal continuous annular pole pieces of opposite sign, each terminating in an annular extremity of re duced area and together forming a conical aperture, a conical screen journaled to rotate in proximity to the pole pieces, an in ternal fixed armature exteriorly of substantially' conical'form, whereby the lines of magnetic force between the armature and pole pieces converge toward the pole pieces, means for feeding material to be separated between the armature and screen and means for separately receiving the materials flowing over the armature by gravity and the materials discharged from the screen by centrifugal force.

JOSEPH W EATHERBY, J R. \Vitnesses THoMAs DURANT, ALEXANDER S. STEUART. 

